Defect study of GaInP/GaAs based heterojunction bipolar transistor emitter layer

Defects in the emitter region of $Ga0.51In0.49P/GaAs$ heterojunction bipolar transistors (HBTs) were investigated by means of deep-level transient spectroscopy. Both annealed (635 °C, 5 min) and as grown metalorganic chemical vapor deposition epitaxial wafers were investigated in this study, with an electron trap observed in the HBT emitter space-charge region from both wafers. The deep-level activation energy was determined to be $0.87±0.05 eV$ below the conduction band, the capture cross section $3×10−14 cm2$ and the defect density of the order of $1014 cm−3.$ This defect was also found to be localized at the emitter–base interface.